How Claude Code Sub-agents Work: Context Isolation, Frontmatter Definitions, Background Execution, and Permission Inheritance
Sub-agents are specialized assistants that work in their own context window: a single Markdown file defines their system prompt, tools, and model. Claude delegates automatically based on the description field, or you can @-mention to force one. This post breaks down the frontmatter schema, background execution and nested spawning, permission inheritance rules, and when not to use them.